Isn't it so sad that the NPC gods didn't get a chance to harness the power of the elements and offer infusion boons? Here's the solution
Have three of all standard elements and gain access to an additional cast to decimate your foes!
While you have more Earth/Fire/Water/Air than any other element, deal +25% damage!
Once you gain at least seven of any element, upgrade all of your Olympian infusion boons into more effective versions (+50% potency)!
For every element you have more than 8 of, revive a foe after killing it and have it aid you in the fight!